[PMSH] Refactor subscription processor and policy response handler

Signed-off-by: ERIMROB <robertas.rimkus@est.tech>
Change-Id: I91964848df8f7455169650b138b46d8dfc326b6f
Issue-ID: DCAEGEN2-1820

1 files changed, 84 insertions, 0 deletions

diff --git a/components/pm-subscription-handler/pmsh_service/mod/policy_response_handler.py b/components/pm-subscription-handler/pmsh_service/mod/policy_response_handler.py
new file mode 100644
index 00000000..aa5a8cb8
--- /dev/null
+++ b/components/pm-subscription-handler/pmsh_service/mod/policy_response_handler.py
@@ -0,0 +1,84 @@
+# ============LICENSE_START===================================================
+#  Copyright (C) 2020 Nordix Foundation.
+# ============================================================================
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+# ============LICENSE_END=====================================================
+
+import json
+
+from tenacity import retry, wait_fixed, retry_if_exception_type
+
+import mod.pmsh_logging as logger
+from mod.network_function import NetworkFunction
+from mod.subscription import Subscription, AdministrativeState, subscription_nf_states
+
+
+policy_response_handle_functions = {
+    AdministrativeState.LOCKED.value: {
+        'success': NetworkFunction.delete,
+        'failed': Subscription.update_sub_nf_status
+    },
+    AdministrativeState.UNLOCKED.value: {
+        'success': Subscription.update_sub_nf_status,
+        'failed': Subscription.update_sub_nf_status
+    }
+}
+
+
+class PolicyResponseHandler:
+    def __init__(self, mr_sub, subscription_name, app):
+        self.mr_sub = mr_sub
+        self.subscription_name = subscription_name
+        self.app = app
+
+    @retry(wait=wait_fixed(5), retry=retry_if_exception_type(Exception))
+    def poll_policy_topic(self):
+        """
+        This method polls MR for response from policy. It checks whether the message is for the
+        relevant subscription and then handles the response
+        """
+        self.app.app_context().push()
+        administrative_state = Subscription.get(self.subscription_name).status
+        try:
+            response_data = self.mr_sub.get_from_topic('policy_response_consumer')
+            for data in response_data:
+                data = json.loads(data)
+                if data['status']['subscriptionName'] == self.subscription_name:
+                    nf_name = data['status']['nfName']
+                    response_message = data['status']['message']
+                    self._handle_response(self.subscription_name, administrative_state,
+                                          nf_name, response_message)
+        except Exception as err:
+            raise Exception(f'Error trying to poll policy response topic on MR: {err}')
+
+    @staticmethod
+    def _handle_response(subscription_name, administrative_state, nf_name, response_message):
+        """
+        Handles the response from Policy, updating the DB
+
+        Args:
+            subscription_name (str): The subscription name
+            administrative_state (str): The administrative state of the subscription
+            nf_name (str): The network function name
+            response_message (str): The message in the response regarding the state (success|failed)
+        """
+        logger.debug(f'Response from MR: Sub: {subscription_name} for '
+                     f'NF: {nf_name} received, updating the DB')
+        try:
+            sub_nf_status = subscription_nf_states[administrative_state][response_message].value
+            policy_response_handle_functions[administrative_state][response_message](
+                subscription_name=subscription_name, status=sub_nf_status, nf_name=nf_name)
+        except Exception as err:
+            raise Exception(f'Error changing nf_sub status in the DB: {err}')